Growers and packers in the apple industry in the Pacific Northwest have standardized on wooden agricultural containers or bins since about 1957. In the orchard, apple pickers place freshly picked apples in the bins. The bins are taken to the packing house where they are sometimes emptied and the contents go through the regular packing process. Other times, the apples are sorted for size and grade and then the bins are refilled and placed in controlled atmosphere storage.
The standard wooden bin has interior dimensions of 47" wide, 47" long and 281/2 inches in height. The wooden bins are fastened together with glue, nails, rivets and metal brackets.
Wooden bins suffer from certain disadvantages, such as:
a) Wood construction is subject to cracking and warpage. PA1 b) A single bin may absorb 12 pounds of water during the first three months of controlled atmosphere storage. This moisture comes from the fruit and its loss promotes fruit shrivel. PA1 c) Wood construction does not permit the recommended 8% to 11% free air space on the sides and bottom. This results in slower cooling of the bin contents, and increases difficulty in maintaining low temperatures during controlled atmosphere storage. PA1 d) Wood promotes contamination problems by absorbing chemicals used in orchard and packing house operations. PA1 e) Wood bins are often difficult and time consuming to repair. PA1 f) Most wooden bins lack a bin interlocking feature that would promote stability when the bins are stacked one on another. PA1 g) Wooden bins are not recyclable. PA1 h) Dry wooden bins create fire hazards in bin storage areas. PA1 a) Plastic does not absorb moisture which assists in the control of humidity during storage and enhances fruit quality. PA1 b) With at least 10% free air space in the sides and bottom, the plastic bin allows faster cooling in storage, and assists in maintaining uniform low temperatures in the storage building. PA1 c) Smooth interior wall and floor surfaces permit easy cleaning and reduce the potential for contamination caused by decay organisms which often are present in wood bins. PA1 d) A molded interlocking feature permits safer storage and transport of vertically stacked bins. PA1 e) The plastic can be recycled into new bins.
The advantages of a plastic bin are:
All of the above disadvantages of wooden bins and advantages of plastic bins are set forth in `STUDIES ON APPLE BINS` by Dr. Alan F. Hauff, published by the Washington State Horticultural Association.